Serum Levels of IL-17 and IL-23 in Patients With Rheumatic Mitral Stenosis

Plausible Role of NLRP3 Inflammasome and Associated Cytokines in Pathogenesis of Rheumatic Heart Disease

Rheumatic heart disease (RHD) is a post-streptococcal sequela caused by Streptococcus pyogenes. The global burden of disease is high among people with low socio-economic status, with significant cases emerging every year despite global eradication efforts. The current treatment includes antibiotic therapies to target strep throat and rheumatic fever and valve replacement strategies as a corrective measure for chronic RHD patients. Valvular damage and valve calcification are considered to be the end-stage processes of the disease resulting from impairment of the endothelial arrangement due to immune infiltration. This immune infiltration is mediated by a cascade of events involving NLRP3 inflammasome activation. NLRP3 inflammasome is activated by wide range of stimuli including bacterial cell wall components like M proteins and leukocidal toxins like nicotinamide dehydrogenase (NADase) and streptolysin O (SLO) and these play a major role in sustaining the virulence of Streptococcus pyogenes and progression of RHD. In this review, we are discussing NLRP3 inflammasome and its plausible role in the pathogenesis of RHD by exploiting the host-pathogen interaction mainly focusing on the NLRP3 inflammasome-mediated cytokines IL-1β and IL-18. Different therapeutic approaches involving NLRP3 inflammasome inactivation, caspase-1 inhibition, and blockade of IL-1β and IL-18 are discussed in this review and may be promising for treating RHD patients.

The Role of Inflammation and Oxidative Stress in Rheumatic Heart Disease

Rheumatic heart disease (RHD), an acquired valvular disease, remains an important cause of morbidity and mortality in developing countries. This chronic illness starts from untreated streptococcal throat infection, resulting in acute rheumatic fever (ARF) in susceptible individuals. Repeated infections lead to a chronic phase characterized by the damage of heart valves. Inflammation has been found to play important role in the development of this disease. All the studies presented in this review clearly show the involvement of the inflammatory state in the progression of this disease. However, the exact role of cytokines in inflammation sites remains to be examined, since most studies have so far focused on peripheral blood. Such analysis would provide information on inflammatory mechanisms in situ.

Cytokine imbalance in acute rheumatic fever and rheumatic heart disease: Mechanisms and therapeutic implications

Acute Rheumatic Fever (ARF) and Rheumatic Heart Disease (RHD) are autoimmune sequelae of Group A Streptococcus infection with significant global disease burden. The pathogenesis of these diseases is poorly understood, and no immune modulating therapies are available to stop progression from ARF to RHD. Cytokines and chemokines are immune signaling molecules critical to the development of autoimmune diseases. An increasing number of studies point to a central role for pro-inflammatory cytokines and chemokines in ARF and RHD pathogenesis, in particular IL-6, IL-8/CXCL8, and TNFα, which are elevated in circulation in both ARF and RHD patients. Histological studies of RHD valve tissue implicates Th1 and Th17 associated pro-inflammatory cytokines, chemokine CXCL9, and the fibrosis-associated cytokine TGF-β in progressive cycles of inflammatory damage and fibrotic repair. Taken together, this suggests immune molecules contribute to both the acute inflammatory disease stage of ARF, as well as cardiac remodeling and valve dysfunction in RHD. Monoclonal antibody blockade of pro-inflammatory cytokines IL-6 and TNFα are approved therapies for many autoimmune diseases and the most successful immunomodulating therapies for rheumatoid arthritis. Current evidence suggests possible benefit for ARF patients from IL-6 and TNFα blockade, in particular to interrupt progression to RHD, and warrants immediate investigation.

Systemic cytokines, chemokines and growth factors reveal specific and shared immunological characteristics in infectious cardiomyopathies

Heart disease is a major cause of death worldwide. Chronic Chagas cardiomyopathy (CCC) caused by infection with Trypanosoma cruzi leading to high mortality in adults, and rheumatic heart disease (RHD), resulting from infection by Streptococcus pyogenes affecting mainly children and young adults, are amongst the deadliest heart diseases in low-middle income countries. Despite distinct etiology, the pathology associated with both diseases is a consequence of inflammation. Here we compare systemic immune profile in patients with these cardiopathies, to identify particular and common characteristics in these infectious heart diseases. We evaluated the expression of 27 soluble factors, employing single and multivariate analysis combined with machine-learning approaches. We observed that, while RHD and CCC display higher levels of circulating mediators than healthy individuals, CCC is associated with stronger immune activation as compared to RHD. Despite distinct etiologies, univariate analysis showed that expression of TNF, IL-17, IFN-gamma, IL-4, CCL4, CCL3, CXCL8, CCL11, CCL2, PDGF-BB were similar between CCC and RHD, consistent with their inflammatory nature. Network analysis revealed common inflammatory pathways between CCC and RHD, while highlighting the broader reach of the inflammatory response in CCC. The final multivariate model showed a 100% discrimination power for the combination of the cytokines IL-12p70, IL-1Ra, IL-4, and IL-7 between CCC and RHD groups. Thus, while clear immunological distinctions were identified between CCC and RHD, similarities indicate shared inflammatory pathways in these infectious heart diseases. These results contribute to understanding the pathogenesis of CCC and RHD and may impact the design of immune-based therapies for these and other inflammatory cardiopathies that may also share immunological characteristics.

Randomised controlled trial into the role of ramipril in fibrosis reduction in rheumatic heart disease: the RamiRHeD trial protocol

INTRODUCTION

Rheumatic heart disease (RHD) is a major burden in developing countries and accounts for 80% of all people living with the disease, where it causes most cardiovascular morbidity and mortality in children and young adults. Chronic inflammation and fibrosis of heart valve tissue due to chronic inflammation in RHD will cause calcification and thickening of the impacted heart valves, especially the mitral valve. This fibrogenesis is enhanced by the production of angiotensin II by increased transforming growth factor β expression and later by the binding of interleukin-33, which is known to have antihypertrophic and antifibrotic effects, to soluble sST2. sST2 binding to this non-natural ligand worsens fibrosis. Therefore, we hypothesise that ACE inhibitors (ACEIs) would improve rheumatic mitral valve stenosis.

METHODS AND ANALYSIS

This is a single-centre, double-blind, placebo-controlled, randomised clinical trial with a pre-post test design. Patients with rheumatic mitral stenosis and valve dysfunction will be planned for cardiac valve replacement operation and will be given ramipril 5 mg or placebo for a minimum of 12 weeks before the surgery. The expression of ST2 in the mitral valve is considered to be representative of cardiac fibrosis. Mitral valve tissue will be stained by immunohistochemistry to ST2. Plasma ST2 will be measured by ELISA. This study is conducted in the Department of Cardiology and Vascular Medicine, Universitas Indonesia, National Cardiac Center Harapan Kita Hospital, Jakarta, Indonesia, starting on 27 June 2019.

ETHICS AND DISSEMINATION

The performance and dissemination of this study were approved by the ethics committee of National Cardiovascular Center Harapan Kita with ethical code LB.02.01/VII/286/KEP.009/2018.

TRIAL REGISTRATION NUMBER

NCT03991910.

Serum Thiol Levels and Thiol/Disulfide Homeostasis in Patients with Rheumatic Mitral Valve Disease and Healthy Subjects

Fundamento

A doença valvar mitral reumatismal (DVMR) é a apresentação mais comum das doenças cardíacas reumáticas (DCR). Os processos de inflamação e fibrose também têm papéis significativos em sua patogênese. Estudos recentes demonstram que os tióis e o tiol-dissulfeto são marcadores de stress oxidativo inéditos e promissores.

Objetivos

O objetivo deste estudo foi avaliar diferenças entre os níveis de tiol sérico e de tiol-dissulfeto em pacientes com DVMR e no grupo de controle.

Métodos

Noventa e dois pacientes com DVMR foram cadastrados no estudo. Cinquenta e quatro sujeitos saudáveis, e com correspondência de sexo e idade em relação ao grupo de estudo, também foram incluídos no estudo como um grupo de controle. Foram investigados os níveis de tiol nos pacientes com DVMR e o grupo de controle. Os p-valores menores que 0,05 foram considerados estatisticamente significativos.

Resultados

Os pacientes com DVMR apresentaram pressão sistólica da artéria pulmonar (PSAP) e níveis de diâmetro do átrio esquerdo (AE) mais altos que os do grupo de controle. Os níveis de tiol nativo (407±83 μmol/L vs. 297±65 μmol/L, p<0,001) e tiol total (442±82 μmol/L vs. 329±65 μmol/L, p<0,001) são mais altos no grupo de controle. Níveis de dissulfeto (16,7±4,9 μmol/L vs. 14,8±3,7 μmol/L, p=0,011) são mais altos no grupo de pacientes com DVMR. Foi identificada uma correlação positiva entre as razões dissulfeto/tiol nativo e dissulfeto/tiol total com PSAP, diâmetro de AE, e gravidade da EMi. A razão dissulfeto/tiol total é significativamente mais alta em pacientes com EMi grave que em pacientes com EMi leve a moderada.

Conclusões

Até onde se sabe, este é o único estudo que avaliou a homeostase tiol/dissulfeto como um preditor inédito, que está relacionado de forma mais próxima à DVMR e à gravidade da EMi.

Detecting sub-clinical disease activity in patients with chronic rheumatic valvular heart disease

OBJECTIVE

Valve disease progression in rheumatic heart disease(RHD) is generally attributed to recurrent attacks of acute rheumatic fever(ARF). However, persistence of chronic sub-clinical inflammation remains a plausible but unproven cause. Non-invasive means to identify sub-clinical inflammation may facilitate research efforts towards understanding its contribution to disease progression.

METHODS

Patients with chronic RHD, without clinical evidence of ARF, undergoing elective valve surgery were enrolled. Sub-clinical inflammation was ascertained by histological evaluation of left atrial appendage and valve tissue excised during surgery. We assessed the diagnostic utility of Gallium-67 scintigraphy imaging, and inflammatory biomarkers, hsCRP, IL-2, IL-6, Tumor Necrosis Factor-Alpha(TNF-α), Interferon-gamma(IFN-γ), and Serum Amyloid A(SAA), in identifying patients with sub-clinical inflammation.

RESULTS

Of the 93 RHD patients enrolled(mean age 34 ± 11 years, 45% females), 86 were included in final analysis. Sub-clinical inflammation was present in 27 patients(31.4%). Patients with dominant regurgitant lesions were more likely to have sub-clinical inflammation compared to those with stenotic lesions, though this association was not statistically significant(dominant regurgitant lesions vs isolated mitral stenosis: OR 3.5, 95%CI 0.68-17.96, p = 0.133). Inflammatory biomarkers were elevated in the majority of patients: hsCRP, IL-2, IL-6, TNF-α, and IFN-γ in 44%, 89%, 90%, 79%, and 81% patients, respectively. However, there was no significant association between biomarker elevation and histologically ascertained sub-clinical inflammation. Ga-67 imaging was unable to identify inflammation in the 15 patients in whom it was performed.

CONCLUSION

Sub-clinical inflammation is common in RHD patients. Conventional inflammatory markers are elevated in the majority, but aren't discriminatory enough to identify the presence of histologic inflammation.

Decreased Cytokine Plasma Levels and Changes in T-Cell Activation Are Associated With Hemodynamic Improvement and Clinical Outcomes After Percutaneous Mitral Commissurotomy in Patients With Rheumatic Mitral Stenosis

Mitral stenosis (MS) is a consequence of rheumatic heart disease that leads to heart failure requiring mechanical intervention. Percutaneous mitral commissurotomy (PMC) is the treatment of choice for the intervention, and currently there are no soluble markers associated with hemodynamic improvement after PMC. This study aims to determine the changes in cytokine/chemokine plasma levels, as well as T cell activation after PMC, and to investigate their association with immediate hemodynamic improvement and clinical outcomes. Plasma samples from eighteen patients with well-defined MS who underwent PMC and 12 healthy controls were analyzed using BioPlex immunoassay. We observed that 16 out of the 27 (60%) molecules assessed were altered in patients' plasma pre-PMC as compared to control group. Of those, IL-1β, IL-12, IL-6, IL-4, PDGF, and CCL11 showed significant decrease after PMC. Stratifying the patients according to adverse outcome after a 28-month median follow up, we detected a significant reduction of IL-1β, IL-12, IL-6, IL-4, IFN-γ, CXCL-10, VEGF, FGF and PDGF post-PMC in patients without events, but not in those who presented adverse events during the follow-up. Patients with adverse outcomes had lower IL-10 pre-PMC, as compared to the ones without adverse events. In addition, the frequency of CD8+ activated memory cells was increased after PMC, while the frequency of CD4+ activated memory cells did not change. Our results show an association between the decrease of specific cytokines and changes in T cell activation with hemodynamic improvement post-PMC, as well as with long-term outcomes, suggesting their possible use as soluble markers for hemodynamic recovery after MS intervention.

Mechanistic implications of altered protein expression in rheumatic heart disease

Rheumatic heart disease (RHD) is a major cause of cardiovascular morbidity and mortality in low- and middle-income countries, where living conditions promote spread of group A β-haemolytic streptococcus. Autoimmune reactions due to molecular mimicry of bacterial epitopes by host proteins cause acute rheumatic fever (ARF) and subsequent disease progression to RHD. Despite knowledge of the factors that predispose to ARF and RHD, determinants of the progression to valvular damage and the molecular events involved remain incompletely characterised. This review focuses on altered protein expression in heart valves, myocardial tissue and plasma of patients with RHD and pathogenic consequences on RHD. Proteins mainly involved in structural organization of the valve matrix, blood homeostasis and immune response were altered due to RHD pathogenesis. Study of secreted forms of these proteins may aid the development of non-invasive biomarkers for early diagnosis and monitoring outcomes in RHD. Valve replacement surgery, the single evidence-based strategy to improve outcomes in severe RHD, is costly, largely unavailable in low- and middle-income countries (LMIC) and requires specialised facilities. When diagnosed early, penicillin prophylaxis may be used to delay progression to severe valvular damage. Echocardiography and cardiovascular magnetic resonance and the standard imaging tools recommended to confirm early diagnosis remain largely unavailable and inaccessible in most LMIC and both require expensive equipment and highly skilled persons for manipulation as well as interpretation of results. Changes in protein expression in heart valves and myocardium are associated with progressive valvular deformation in RHD. Understanding these protein changes should shed more light on the mechanisms of pathogenicity, while secreted forms of these proteins may provide leads towards a biomarker for non-invasive early detection of RHD.

Inhibition of miR‑155‑5p attenuates the valvular damage induced by rheumatic heart disease

Autoimmunity is involved in the valvular damage caused by rheumatic heart disease (RHD). Increased evidence has linked microRNAs (miRNAs/miRs) to autoimmune disease. Signal transducer and activator of transcription 3 (STAT3) and sphingosine-1-phosphate receptor 1 (S1PR1) and suppressor of cytokine signaling 1 (SOCS1) have been widely studied for their roles in autoimmunity and inflammation. Thus, the current study aims to investigate the role played by miR-155-5p in RHD-induced valvular damage via the S1PR1, SOCS1/STAT3 and interleukin (IL)-6/STAT3 signaling pathways. An RHD rat model was induced by inactivated Group A streptococci and complete Freund's adjuvant. A recombinant adeno-associated virus (AAV-miR155-inhibitor) was used to inhibit the expression of miR-155-5p in the heart. Inflammation and fibrosis were assessed by hematoxylin and eosin staining and Sirius red staining. The expression of miR-155-5p in valvular tissues and serum exosomes was detected by reverse transcription-quantitative PCR. S1PR1, SOCS1, STAT3, phosphorylated STAT3, IL-6 and IL-17 protein expression was detected by western blotting and immunohistochemistry. The relationships between miR-155-5p and S1PR1 and SOCS1 were detected by dual luciferase assays. Cytokine concentrations were measured by ELISA. The expression of miR-155-5p in valve tissues and serum exosomes was increased along with decreased S1PR1 and activated SOCS1/STAT3 signaling in the RHD model. The expression of IL-6 and IL-17 was increased in the valves and the serum. Dual luciferase assays showed that miR-155-5p directly targeted S1PR1 and SOCS1. Inhibition of valvular miR-155-5p through AAV pretreatment increased S1PR1 expression and inhibited activation of the SOCS1/STAT3 signal pathway as a result of attenuated valvular inflammation and fibrosis as well as a decrease in IL-6 and IL-17 in the valves and serum. These results suggest that inhibition of miR-155-5p can reduce RHD-induced valvular damage via the S1PR1, SOCS1/STAT3 and IL-6/STAT3 signaling pathways.

Group G Streptococcus Induces an Autoimmune Carditis Mediated by Interleukin 17A and Interferon γ in the Lewis Rat Model of Rheumatic Heart Disease

Acute rheumatic fever and rheumatic heart disease (ARF/RHD) have long been described as autoimmune sequelae of Streptococcus pyogenes or group A streptococcal (GAS) infection. Both antibody and T-cell responses against immunodominant GAS virulence factors, including M protein, cross-react with host tissue proteins, triggering an inflammatory response leading to permanent heart damage. However, in some ARF/RHD-endemic regions, throat carriage of GAS is low. Because Streptococcus dysgalactiae subspecies equisimilis organisms, also known as β-hemolytic group C streptococci and group G streptococci (GGS), also express M protein, we postulated that streptococci other than GAS may have the potential to initiate or exacerbate ARF/RHD. Using a model initially developed to investigate the uniquely human disease of ARF/RHD, we have discovered that GGS causes interleukin 17A/interferon γ-induced myocarditis and valvulitis, hallmarks of ARF/RHD. Remarkably the histological, immunological, and functional changes in the hearts of rats exposed to GGS are identical to those exposed to GAS. Furthermore, antibody cross-reactivity to cardiac myosin was comparable in both GGS- and GAS-exposed animals, providing additional evidence that GGS can induce and/or exacerbate ARF/RHD.

Association of matrix metalloproteinase 3 and endogenous inhibitors with inflammatory markers in mitral valve disease and calcification

Calcific mitral valve stenosis (MVS) is a common disease characterized by extensive remodeling of the extracellular matrix via matrix metalloproteinases (MMPs). The mechanism of calcification due to extensive matrix remodeling remains unclear. In this study, we investigated the relationship between MMP-3, tissue inhibitors of metalloproteinases (TIMPs) as well as pro-inflammatory cytokines and the phenomenon of calcification in MVS. 212 patients having rheumatic mitral stenosis (RMS) and 155 healthy control subjects were recruited in the Cardiology Department of La Rabta Hospital University. Levels of MMP-3, TIMPs, IL-6 and TNF-α were measured by ELISA sandwich assay, hs-CRP was measured by immunoturbidimetry. Plasma levels of MMP-3, TIMP-1 and MMP-3/TIMP-2 ratio were lower only in RMS women in comparison to the control group. Calcification degree correlated positively with MMP-3 in women and men. In addition, calcification was correlated positively with MMP-3/TIMPs ratio in women patients. The inflammatory parameters were positively associated with extracellular matrix turnover biomarkers in men patients. In patients, the level of MMP-3 was increased in men and women with a calcification score ≥ 5. In addition, MMP-3 level predicted the occurrence of calcification. At ROC curves analysis, the cut-off MMP-3 level was in women was 9.21 ng/ml (sensitivity 51.1%, specificity 89.3%) and in men was 12.84 ng/ml (sensitivity 78.6%, specificity 77.8%). The high levels of MMP-3 and the biomarkers of inflammation contribute to valvular remodeling and calcification of the mitral valve.